1. John Wilde CEO, DW International
GNSS Integrity
John Wilde
CEO, DW International

2. Agenda About DW International Basic GNSS Principles
Navigation System Performance – RNP
RAIM on the Ground - Performance Prediction
GNSS RAIM/RNP Prediction Tool

3. DW International In-house Expertise in Aviation Started in 2005
Consultancy for:
Air Navigation
Civil Air Communications
Air Traffic Management
In-house Expertise in Aviation
Array of External Consultants
International Presence
ISO 9001:2008 Certified

4. Expertise
Navigation (PBN)
Airworthiness and Operational Approval
Aviation Safety
Communications
Surveying / Geodesy
Instrument Procedure Design
Airspace Design
GNSS Policy Making
ATM Consultancy
Spectrum

5. Consultancy RNAV 1 / RNAV 2 Navigation Specification
PBN Criteria for PANS-OPS
Editorial Reviews for ICAO PBN Manual + RNP AR Procedure Design Manual
P-RNAV Safety Case
RF Spectrum Expertise
Technical Advisor to EUROCONTROL IFPP Member
Chairmanship of CGSIC

6. Agenda About DW International Basic GNSS Principles
Navigation System Performance – RNP
RAIM on the Ground - Performance Prediction
GNSS RAIM/RNP Prediction Tool

7. The GPS Timeline
1973
1978
1983
1991
1995
2000
2003
2005
2009 L5
L2C
2nd Gulf War
SA Switched Off
GPS Fully Operational July 1995
1st Gulf War
President Ronald Reagan ordered the U.S. military to make the Global Positioning System (GPS) available for civilian use so that navigational errors like that of KAL 007 could be averted in the future.
KAL 007 Shot Down
1st GPS Satellite Launched
GPS Initial Approval December 1973

8. How does GPS work?

9. Multiple Satellites for Position

10. Error Source GPS Error (m) Error Sources Ephemeris 1 to 3 Ionosphere
Troposphere
0.1 to 0.5
Multi-path
0.5 to 1.5
Satellite Clock
1 to 2
Receiver Noise
0.2 to 0.3

11. Agenda About DW International Basic GNSS Principles
Navigation System Performance – RNP
RAIM on the Ground - Performance Prediction
GNSS RAIM/RNP Prediction Tool

12. Navigation System Performance - RNP
Traditionally “box-based”
Mandatory equipment
Performance not specified explicitly
Move towards Required Navigation Performance or Performance-Based Navigation
Operator can meet requirements in ‘anyway he pleases’
e.g. with GPS
Goal: Target Level of Safety
Risk of leaving containment area distributed amongst:
Accuracy
Integrity
Continuity
Availability

13. Navigation System Performance - Accuracy

14. Accuracy: Lateral

15. Accuracy: Geometry

16. Accuracy: Geometry

17. Navigation System Performance - Integrity

18. Navigation System Performance - Continuity

19. Continuity
Continuity risk is the probability of a detected but unscheduled navigation function interruption after an operation has been initiated
RAIM: detected failure causes loss of continuity - but preserves integrity

20. Navigation System Performance - Availability

21. Agenda About DW International Basic GNSS Principles
Navigation System Performance – RNP
RAIM on the Ground - Performance Prediction
GNSS RAIM/RNP Prediction Tool

22. RAIM on Ground - Performance Prediction
Average (expected) performance depends mainly on
Geometry (time-varying)
Measurement quality (constant)
Satellite failure rate (constant)
Geometry is predictable
Expected performance is predictable
Prediction does not include effect of real-time events
Sudden satellite failures
Can be performed on the ground as a pre-flight check

23. RAIM (integrity) Holes

24. Agenda About DW International Basic GNSS Principles
Navigation System Performance – RNP
RAIM on the Ground - Performance Prediction
GNSS RAIM/RNP Prediction Tool

25. GRPS : On-Demand Service
GRPS = GNSS RAIM / RNP Prediction Service
Web interface and automated XML interface
Current website implementation for GPS constellation only
Future implementation for other GNSS to meet demand
e.g. GLONASS, Galileo, COMPASS
Fully integrated XML solution for
Airlines
Air Navigation Data Providers
Flight planning companies
Both do RAIM predictions down to 0.1 NM

26. RAIM in Aviation: ICAO RNP Requirements

27. GRPS Dynamic and flexible High load capacity, high availability
Tailorable to the requirements of the data provider and their client base
High load capacity, high availability
Hosted in professional data centres, load-balanced
Includes planned and short-notice outage information
Latest constellation almanacs and NANUs supplied by the US Coastguard
All calculations are performed in real time and not on a pre-calculated grid
Routes and Airports capability

28. GRPS: On-Demand Service
Both services support both RAIM prediction algorithms common in GPS devices:
Fault Detection (FD):
Used by traditional RAIM to detect faults (differences between a satellite’s pseudo range measurement and its expected value)
Minimum 5 satellites in view
Fault Detection and Exclusion (FDE):
Used by newer GPS receivers to allow continued operation in the presence of a GPS failure
Minimum 6 satellites in view
Baro aided, SA on/off, mask angle, etc
Avionic specifics for RNP AR

29. Architecture

30. GRPS: Comparison with AUGUR
DWI GRPS
Coverage Area
ECAC Airspace Only
Global
Constellation Status Check
Yes
Constellation Visibility Check
Aerodrome Check
RAIM Only
Terminal: 1.0 NM
NPA: 0.3 NM
RAIM and RNP
En-route: 2.0 NM
MNPS
RNAV5
RNP10: 10 NM
RNP4: 4 NM
RNP(AR): NM
Route RAIM Check
Max. Fidelity of RAIM/RNP Prediction
NPA 0.3 NM
RNP(AR) 0.1 NM
Configurable Receiver Parameters
C129-FD
C145/146-FDE
Baro / Non-Baro Aided
C129-FD/FDE, SA On/Off
C145/146-FDE, SA Off
RAIM/RNP Calculations Compliant with ICAO PBN Manual
Partial
Aeronautical Data Provider
Jeppesen
(Possible move to
Eurocontrol’s EAD in 2012)
GPS Constellation Data Provider
USCG

31. https://tools.dwint.com/grps/
GRPS Web Access
Customisable – e.g. ICAO SAM Region

32. Eurocontrol

33. Web Tools AUGUR SAFIRE Final Approach Segment Database (FAS DB)
Web-based RAIM Prediction Tool
SAFIRE
Web-based, secure communications Frequency Management Tool
Final Approach Segment Database (FAS DB)
Final Approach Segment Data Block Tool – Web- based Tool to generate CRC values

34. RNAV Validation Tool
Desktop ground RNAV Procedure Validation application
PANS-OPS criteria
Flyability
Noise contours
Fuel Flow
Emissions

35. GNSS Performance Monitoring System
GPMS
Allows users to comply with ICAO Guidance – Annex 10
Requires Monitoring and Recording of GNSS Data as Navigation Aids and for incident investigation
Localised GNSS Receivers
Wide Area RAIM Prediction
GNSS NOTAMS for State ANSP and Airspace users
Ionospheric data collection and alerting

36. GNSS Performance Monitoring System
Incheon International Airport, Seoul, Korea
Hong Kong International Aiport

37. GNSS Performance Monitoring System

38. Obrigado - Any questions?